1. Field
This device pertains to lighting for photography, cinematography, and videography, specifically to light diffusers, and more specifically light diffusers for lightweight, highly portable lighting fixtures.
2. Prior Art
In the fields of cinematography, videography, and photography, one of the essentials of the craft is having illumination of sufficient intensity and appropriate quality to expose the image in the desired manner. It is commonly agreed that an essential element of these crafts is being able to soften the sources of illumination. Another essential element of these crafts is being able to deliver a high quality image even with a minimal crew. Yet another important element of these crafts is being able to prevent light from falling on undesired areas of the image. The prior art in this field addresses only some of these essential needs, since these needs are often at odds with each other.
There are a wide variety of lighting instruments, luminaires and flashes that answer to the need of portable, convenient illumination. Many of these luminaires are small and lightweight, to meet the need for portability, and some of those are battery powered, in order to be even more portable. Many photographers, videographers, and cinematographers find these highly portable luminaires particularly useful, since they may be working either on their own or with a very small crew where mobility and flexibility are at a premium.
However, in order to be portable, most of these luminaires are very small. It is generally understood in the craft that a small light source, such as a single, unshaded light bulb, is “hard”, where the shadows are hard-edged and clearly defined. Examples of highly portable luminaires are seen in U.S. Pat. Nos. 7,163,302 (2005) and 7,331,681 (2008) to Pohlert et al., 3,550,519 to Lewis (1970), 4,485,336 (1984) to Yoshiyama et al.
The need to soften or diffuse light sources has been addressed by the prior art, but with some limitations. It is understood that the light from a larger light source such as a paper lantern, is “soft”, where the light falls onto the subject from a plurality of directions, wrapping around the contours of the subject, making softly-defined shadows. The studio lighting industry has many techniques that answer this need, but most involve freestanding equipment and crew members to set them up, and are thus unsuitable for the solo operator or small crew, such as a news cameraman or reality-television camera crew. The prior art offers a number of ways to make a light source larger, usually by bouncing the light off of a larger reflective surface or by passing the light through a translucent membrane or panel. Examples are U.S. Pat. Nos. 4,446,506 to Larson (1984), 5,023,756 to Regester (1991), 5,311,409 to King (1994), 6,076,935 to Kester (2000).
However, none of the prior art is optimal for the solo cameraman in that these inventions are all composed of fabric supported by metal rods and rings or else of rigid panels, giving them some degree of weight, bulk, and inconvenience of setup and transport. Particularly for a light mounted on the handheld camera, very low weight is extremely important. In addition, the prior art all being partially composed of rigid structures or rods, it is difficult to rapidly stow them in the same bag or case as the lighting instrument, and they often necessitate their own bag or case, giving the solo cameraman one more issue to manage.
Maximizing the softness of a light source with minimal loss of light output is also important. All the prior art generally does this using one of two techniques, either bouncing the light off of a large reflective surface onto the subject, or directing the light through a translucent diffusive layer of material towards the subject. Studio lighting technicians have learned that one can often gain a greater degree of softness with less loss of intensity by passing the light through not one heavy diffusive layer but through two thinner layers of diffusive translucent material. None of the prior art has put this technique into effect in the area of lightweight portable light diffusers while still answering the needs of lightweightness of device and controllability of light.
When a light source becomes softer, because it is larger and more diffuse, it necessarily becomes messier, causing light to fall on undesired areas. There is a need to direct the light after softening it. The prior art has answered this need with a variety of devices, such as U.S. Pat. No. 5,556,186 to Pilby (1996), but not for the most lightweight and portable light-diffusing devices. There are other very lightweight light diffusing devices, such as U.S. Pat. No. 4,146,918 to Tureck (1979), but none with the means to control undesired light spill.